Hepatic fibrosis is a serious, potentially irreversible consequence of chronic alcohol abuse. At the cellular level, the onset of alcoholic fibrosis is marked by transformation of hepatic lipocytes (Ito cells, fat-storing cells) from a quiescent to an activated, collagen-producing state. The mechanism whereby lipocytes are activated in alcoholic liver disease remains uncertain. In this application we propose that lipoctyes activation occurs by an "indirect" mechanism involving inflammatory cells (Kupffer cells or neutrophils) as intermediates between hepatocyte and lipocytes. In this scheme inflammatory cells, when exposed to ethanol or by-products of this metabolism, respond by secreting a variety of proteinases. These enzymes digest the extracellular matrix in the hepatic subendothelial space, altering cell-matrix contacts that are critical for maintaining lipocytes in a quiescent state. Alteration of these cell-matrix contacts initiates the process of lipocyte activation. Once lipid aldehydes, and TGFB. The end result is alcoholic liver fibrosis and cirrhosis. The proposed studies will examine the role of inflammatory cells as initiators of lipocyte activation. Our first objective (Specific Aim #1) will be to determine how ethanol leads to hepatic synthesis of the neutrophil chemoattractant IL-8. Hepatocyte and Kupffer cells will be investigated as potential sources of this cytokine; particular attention will be paid to the cellular interactions that may be necessary to induce IL-8 production in the setting of ethanol. In Specific Aim#2 we will characterize the features of lipocyte activation induced by inflammatory cell-derived proteinases. In particular we will determine the extent to which lipocytes are activated by changes in their surrounding extracellular matrix. These experiments will be performed in primary culture, employing the EHS gel as a model of the hepatic matrix in vivo. Specific Aim #3 will address whether ethanol-related stimuli induce proteinases secretion and subsequent lipocyte activation by inflammatory cells. Finally, experiment in Specific Aim #4 will investigate whether neutrophils are essential for initiating lipocyte activation. We expect these experiments to provide important information regarding the rat model of alcoholic liver fibrosis in humans. They should also provide important information regarding the rat model of alcoholic liver injury, yielding insights into the mechanism underlying rat's resistance to alcoholic fibrosis. Perhaps the most important aspect of our Experimental Design is that we examine the effects of putative fibrogenic mediators only on quiescent lipocytes. In so doing we are able to distinguish those compounds that initiate, rather than enhance, lipocyte activation in vivo. Our overall objective is to identify which of the above mechanisms is responsible for initiating hepatic fibrogenesis in the setting of ethanol.